function [mar IR]=marcar_polar(Im,W,alfa)

   [rows,cols] = size(Im);
   cy          = round(rows/2);
   cx          = round(cols/2);
   
   magI = sqrt(real(Im).^2 + imag(Im).^2);
   mar=zeros(rows,cols); 
   
   radius = min(round(rows/2),round(cols/2))-1;
   angle = 360;
   i     = 1;
   
   for r=0:radius
      j = 1;
      for a=0:2*pi/angle: (2*pi) - (2*pi/angle)
         
         if(r>50 && r <90)
           x=cy+round(r*sin(a));
           y=cx+round(r*cos(a));
           
           mar(x,y)= 1;
           magI(i,j)=magI(i,j)*(1+alfa*W(x,y));  
            
           
        
         end
         
         j = j + 1;
      end
      i = i + 1;
   end
   IR=magI;
   
end